Apparatus for automatically coating ceramic rods with metal or metal alloy by thermal evaporation



Sept. 8, 1959 H. LAYER EI'AL E. APPARATUS FOR AUTOMATICALLY COATING CERAMIC RODS WITH METAL 0R METAL ALLOY BY THERMAL EVAPORATION Filed Sept. 10, 1957 2 Sheets-Sheet 1 9 i m 15 3 2 g... 1 u A I ,8 W

2 A L [0 V 00 m I] o z I z a 2:0 8 6 32 3 45 4/ a v l 9 7 '1 -I o o a r a I I e o INVENTORS Sept. 8, 1959 E. H. LAYER ETAL 2,9

' APPARATUS FOR AUTOMATICALLY COATING CERAMIC RODS WITH METAL 0R METAL ALLOY BY THERMAL EVAPORATION File d Sept. 10, 1957 2 Sheets-Sheet 2 INVENTOR5. EDW/l) h. 1.19/55 EREL 0L50 BY United States Patent (lfiice APPARATUS FOR AUTOMATICALLY COATING RODS -WITH vMETAL- OR METAL AL- 'LOY'BY EVAPORATION Edwin H. Layer, Columbus, Ohio, and' Earl, R. Olson, Redondo Beach, Calif,, assignors to the United States of America as represented by the s'ecretary of the-Air Force.

I Application September 10, 1957, Serial No. 683,190 6 Claims. (Cl. 1 18-'-48)- I This invention relates to apparatus forcoat-ingceramic rods suchIas-re'sistor bodies with metal or metal "alloy by, thermal evaporation. This apparatus is adaptable for operation in'a vacuum system.

An importantobject-of'the invention isto-providea machine for partially automatic coating of ceramic rods with metal or metal alloys.

Another object is to provide an apparatus in which ceramic rods or resistor bodiesgare uniformly coated with metallic vapor.

A further object is to provide an apparatus in which the ceramic rods or resistor bodies are individually'coated with a metallicvapor while the rods or bodies are auto matically and continuously travelling through acontainer.

Aistilhfurther object is to'provide an apparatus in which the evaporation of metal or metal alloy' takes place automatically and continuously while therods or resistor bodies are travelling through a'container.

The above objects,,as well, as other objects, features and advantages of the apparatus of this invention will be more clearly apparent in view of the following description and claims when taken in conjunction with the accompanying drawings wherein Figure 1 is a perspective view of the apparatus showing the invention being supported by a frame.

Figure 2 is a second perspective view of the apparatus for coating ceramic rods with metal or metal vapor after being removed from the frame.

Fig. 3 is a schematic end view, partly in section and partly broken away, looking in the direction of the arrow illustrated in Fig. 1 of the drawings, illustrating additional details of the work holder, rod-supporting means, loading buckets and evaporation boat, and the actual mounting for the spreader cams of the inventive apparatus.

Referring now to Figure 1 the reference numeral 1 indicates a suitable metal frame which incloses the invention. Vertically mounted within the frame 1 and rotatably attached thereto is the turntable 2 of the invention comprising the solid disc shaped portion 3 and the hollow disc shaped portion 5. The portion 5 is rigidly attached in substantially parallel relation to the portion 3 at the points 6 and 7 by the spacers 8 and 9.

Referring specifically to Figs. 2 and 3 of the drawings, there is illustrated a work holder indicated generally at 13 and comprising a pair of spring loaded rod-holding means indicated respectively at 12 mounted in the hollow disc portion 5 of the turntable 2 and at 14 located diametrically opposite thereto and mounted in the solid disc portion 3. Both rod-holding means 12 and 14 are mounted in ball bearings loosely enough to allow both axial rotation and longitudinal translation and incorporate spindle shaped chucking means 15 for engaging and holding the ceramic rods 22 to be coated and annular flange means 15a rigidly positioned thereon for respective engagement with the opposite ends of each rod 22 and thereby limit inward movement of said chucking means 15 in each end thereof. The outer sides of rod-holding means latter is being released;

Patented S'ept. 8, 1959 12 and 14 incorporate sheaves18 adapted to be frictionally and drivingly engaged by belts or cables 19 from the driving sheaves 20". The sheaves 20 are so arranged as to be driven by the drive gear 21 at a relatively higher speed than that ofthe turntable 2, .said'tnrntable being frictionally rotated by the. O-ring friction drive 25 past the pair of spreader cams 26 which are rigidly attached to the frame 1 and are shown. schematically in'Fig. 2 and in more detail in Fig. 3. Said spreader cams 26 are actually hidden by the aforesaid frame 'l'as shown in Fig. 1 of-the drawings; however, the cams 26"are'illustrated in Fig. 2 for purposesof showing their adjacent relationship to the hollow disk shaped portion 5 'and' together with the showing in Fig. 3 to. more accurately illustrate their relation to. a ceramic rod 22 when-the The numeral 30designates the evaporation boat adapted to hold the metal to be evaporated, said boat 30" being heated, through theelectrical leads 31. A plurality of evaporation boat loading buckets 32 are rotatably mounted in frame 1 and extend between solid disc 3 and hollow disc 5. A respective boat loading bucket 32 is brought over the evaporation boat 30by operation of the shaft 41 seen in Fig. 1 onwhich shaft 41said pluralityof buckets 32are rotatably mounted. Said shaft 41 is rotated by means of the relatively large pulley 42 affixed thereon, the relatively small pulley 44 afiixed on the adjacently mounted shaft 45 which shaft 45'is driven by the motordriven gear means indicated generally at'46, and the cable 47 betweenpulleys 42'.and 44.' A lever 48 is mounted as shown in Fig. 3' on each of said buckets 32 which lever 48 contacts or engages with a fixed inclined Plane indicated at, 49' as, attached. to said evaporation boat 30. Continued rotatable movement of said bucket 32 effects inversion and unloading thereof to deposit the metal charge carried therein into the evaporation boat 30. These buckets maybe made of tantalum sheet material and mounted on a stainless steel arm so that it may be pivoted and made to unload.

The reference numeral 35 indicates the rod loading station and the numeral 40 indicates the rod discharge station.

In operation, the work holder 13 is spread apart by its movement past the pair of spreader cams 26 mounted upon the frame 1, which engage sheaves 18 (note Fig. 3) thus spreading or separating rod-holding means 12 and 14 from their respective engagement within opposite ends of a selected rod 22 against pressure of the springs indicated at 50 which springs normally maintain engagement therebetween. This spring loading allows the holder 13 to pick up a rod 22 when released at the end of the spreader cams 26. The holder 13 may engage and pick up a new rod 22 by means of the spindle chucking means 15 as further rotational movement continues. Said holder 13, in conjunction with the rotating turntable 2, the spreader cams 26 and the high speed drive indicated schematically at 25 picks up a selected uncoated rod 22 from the loading station 35, spins each rod as it passes over the evaporation boat 30, and deposits the coated rod at the discharge station 40 after chucking means 15 of the work holder 13 is spread apart again by the spreading cams 26. As each rod passes over the evaporation boat 30, the work holder 13 is caused to spin on its axis by means of the pulley and cable arrangement, indicated at 19, 20, and 20', engaging with the sheaves 18 and at the same time, electrical power is applied through leads 31 to the preheated evaporation boat 30, and the entire metal or metal alloy charge such as chromiumtitanium deposited therein from a respective loading bucket 32 is evaporated. The rotating turntable 2 then drives the work holder 13 against a respective spreader earns 26 which engage and spread respective sheaves 18 on chucking means to release the coated rod 22 and deposits it at the discharge station 40. The evaporation boat 30 is then manually recharged with metal for the next evaporation operation.

' It is apparent that the system may be made fully automatic by making available weighed charges for loading, such as pallets.

The above specification and drawings describe a specific embodiment of the invention for purposes of ,explanation, it being apparent that various minor changes may be made therein without departing from the spirit and scope of the invention as defined by the following claims, whereby We claim:

1. In a machine for coating ceramic rods with evaporated metal film, a turntable for rotation about a horizontal axis, power means drivingly connected to continuously rotate said turntable, a work holder rotatably mounted on said turntable, said work holder having axially movable elements incorporating spring means positively holding said elements in engaged position withthe ends of a ceramic rod at a loading station and movable against said spring means toreleas'e the rod at a discharge station, means to feed rods to be coated to the loading station, a metal evaporation boat positioned such that evaporated metal can rise to coat a rod positioned thereover and driving means for rotating the work holder and ceramic rod held thereby while the rod is in the zone of metal evaporated from said boat, and cam means for actuating said work holder to disengage said axially movable elements against the action of said spring means to release the coated rod at the discharge station.

2. Machine as claimed in claim 1 and rotatably mounted bucket means positioned adjacent said turntable and adapted to contain and periodically feed the metal to be evaporated into the said evaporating boat.

3. Machine as claimed in claim 2 in which the means to feed rods to be coated includes an uncoated rod loading station mounted adjacent said cam means so as to simultaneously feed uncoated rods to the work holder after discharge of a preceding coated rod by said cam means.

4. Machine as claimed in claim 3 in which an electrical heating element is interconnected with said metal evaporation boat and adaptable to be energized so as to vaporize the metal delivered thereinto by a respective rotatably mounted bucket means when the rods to be coated are positioned over said evaporating boat in a vapor receiving position.

5. Machine as claimed in claim 4 in which said tumtable comprising a solid rotatably mounted disk portion and a hollow rotatably mounted disk portion positioned parallel to and spaced therefrom and said axially movable elements comprising spaced spindle shaped chucking means loosely mounted respectively in said spaced rotatably mounted disk portions to drivingly engage the ceramic rods, said spring means yieldingly urging said chucking means into driving engagement with the opposite ends of a respective rod and said cam means being mounted stationary relative to said chucking means and constituting a {pair of spaced, parallel spreader cam arms adapted to move the spindle shaped chucking means axially against the urging of said spring means to disengage said rod therefrom.

6. Machine as claimed in claim 5 in which the driving means for rotating the work holder and ceramic rod held thereby while the rod is in the zone of metal evaporated from said boat comprises power driven belts for frictionally driving the spindle-shaped chucking means, said chucking means incorporating a sheave thereon at each end thereof adapted to engage said power driven belts and be driven thereby during a predetermined arc of rotation of said turntable.

No references cited. 

